linux查看流量

#!/bin/bash

###                         ###
###          ###
###   usage:./liuliang.sh eth0  ###
###               ###

if [ $# -ne 1 ];then
   echo Useage : $0 interface
   echo Example: $0 eth0
   exit
fi

while [ "1" ]
do
eth=$1
RXpre=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $2}')
TXpre=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $10}')
sleep 1
RXnext=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $2}')
TXnext=$(cat /proc/net/dev | grep $eth | tr : " " | awk '{print $10}')
clear
echo  -e  "\t RX `date +%k:%M:%S` TX"
RX=$((${RXnext}-${RXpre}))
TX=$((${TXnext}-${TXpre}))

if [[ $RX -lt 1024 ]];then
RX="${RX}b/s"
elif [[ $RX -gt 1048576 ]];then
RX=$(echo $RX | awk '{print $1/1048576 "MB/s"}')
else
RX=$(echo $RX | awk '{print $1/1024 "Kb/s"}')
fi

if [[ $TX -lt 1024 ]];then
TX="${TX}b/s"
elif [[ $TX -gt 1048576 ]];then
TX=$(echo $TX | awk '{print $1/1048576 "MB/s"}')
else
TX=$(echo $TX | awk '{print $1/1024 "Kb/s"}')
fi

echo -e "$eth \t Receive: $RX  Transmit: $TX "
done